In the context of avionic display systems, a Primary Flight Displays (PFD) is typically reserved for the presentation of vital flight information, such as pertinent flight parameters. When generated as a Synthetic Vision PFD or “SV-PFD,” the PFD may include rendered terrain and other features simulating a glass cockpit view; that is, a view from the aircraft cockpit under ideal visibility conditions. Traditionally, a PFD is centered with respect to either aircraft heading or aircraft track. This is appropriate in the context of fixed wing aircraft as disparities between aircraft heading (the direction in which the aircraft is facing) and aircraft track (the direction in which the aircraft is traveling) are typically limited. However, in the context of rotary wing aircraft or “rotorcraft,” it is not uncommon for relatively large disparities or “crab angles” to develop between rotorcraft heading and track. For at least this reason, certain rotorcraft display systems also enable operation of the PFD in a hybrid-centered or split-centered display mode in which the PFD is centered with respect to an intermediary reference point between rotorcraft heading and track. During operation, the rotorcraft display system may actively or automatically switch between PFD centering modes as a function of the disparity between rotorcraft heading and track, the location of nearby obstacles, current air speed, current ground speed, Altitude above Ground Level (AGL), and other such factors.
Switching a PFD between centering modes in the above-described manner can enhance the situational awareness of a pilot by allowing the selection of different centering modes appropriate for varying flight scenarios. However, as a consequence of such PFD mode switching, the particular centering mode in which the PFD is operating at a given juncture in time may not be readily apparent to a pilot when briefly glancing at a PFD. Furthermore, there may exist a relatively pronounced disparity between the Field of View (FOV) of the PFD and the forward-looking, real world view from the rotorcraft cockpit when the PFD operates in a non-heading-centered display mode, such as a track-centered display mode or a hybrid-centered display mode. This disparity may create temporary uncertainty in the mind of a pilot as to the precise relationship between the current heading and track of the rotorcraft. Such pilot uncertainty may be exacerbated when the PFD is generated to include Attitude Director Indicator (ADI) graphics, while Horizontal Situation Indicator (HSI) graphics are generated on or alongside the PFD. In such instances, a mismatch or inconsistency can develop between the orientation of certain symbology included in the ADI graphics (e.g., an ADI heading marker) relative to other symbology contained in the HSI graphics (e.g., the HSI heading marker, the orientation of which is typically fixed) when the PFD operates in a non-heading-centered display mode.
It is thus desirable to provide aircraft display systems and methods for generating enhanced symbology aiding in rapid pilot comprehension of the relationship between aircraft heading and aircraft track across multiple different PFD-centering modes. It would further be desirable if such enhanced symbology could be integrated into the HSI graphics generated on a display device located in the cockpit of a rotorcraft or other aircraft. Other desirable features and characteristics of the present invention will become apparent from the subsequent Detailed Description and the appended Claims, taken in conjunction with the accompanying Drawings and the foregoing Background.